n. 四个构成的一组, 成套的四件, 四胞胎之一

[医] 四胎儿

Quadruplet \Quad"ru*plet\, n. [From {Quadruple}.]
1. A collection or combination of four of a kind.
[Webster 1913 Suppl.]

2. pl. Four children born in the same labor.
[Webster 1913 Suppl.]

3. A cycle for carrying four riders, so arranged that all the
riders can assist in the propulsion.
[Webster 1913 Suppl.]